Augmented reality to alleviate phantom limb pain

People with amputations often suffer from phantom limb pain, a mysterious ailment, experiencing aches and acute pain in a limb that is no longer there. This phantom limb pain could lead the patient to serious chronic conditions, making it notoriously difficult to treat. Various medical and non-medical treatments have been proposed, but in most of the cases, none of them works. However, a team of Swedish researchers has found a new treatment using augmented reality, which is amazingly effective at alleviating phantom limb pain, even the most intractable one.

Phantom motor execution

First proposed in 2014, by Chalmers researcher Max Ortiz Catalan, this therapy method is called ‘phantom motor execution,’ and just finished its first clinical trial. 14 amputees suffering from chronic phantom limb pain, which was unresponsive to other therapy methods, took part in the trial.

How the therapy works

The patients equipped with myoelectric sensors think and act out a gesture. The sensors then detect the signal in muscles that once controlled the missing limb. Artificial Intelligence then decodes the signals and sends the correspondence gesture to the AR interface. The patients then see themselves on a screen with a virtual arm in the place of their missing arm, which they can control in a way they used to control their biological arm. This lets patients reactivate areas of their brains, which were used to move the arm before it was removed. Researchers think that might be the reason that the phantom limb pain reduces. The method is pretty similar to mirror therapy but very sophisticated that, if effect, it allows the patients to play video games with their mind.

The trial was very successful, 50 percent reduction of pain was reported after 12 sessions of the treatment. Also, the majority of patient reported sustain pain reduction at a six-month follow-up.

This augmented reality treatment can be vital not only for reducing pain, but also to let us know what actually happens to our brain when phantom limb pain occurs. Catalan hopes to further prove the results of his study and plans to include leg amputees into the treatment system. Besides, he made relevant code open source to the public, so that it could also be used to treat the patients who need to readapt their movement capability after a stroke, nerve damage or hand injury.